Lesson 1- Rounding Whole Numbers To The Nearest 10

Objective:

At the end of the of this lesson, students should be able to round numbers to the nearest 10.

We can round whole numbers to the nearest 10, 100, 1000 etc. However at this level we will be rounding to the nearest 10 and 100.

ROUNDING TO THE NEAREST 10

When rounding numbers to their nearest 10, it is important to look at the digit in the units column. If the digit is 4 and below (1, 2, 3, 4) we round down. However, if the digit is 5 and above (5, 6, 7, 8, 9) we round it up to the nearest ten.

Example 1:

Round 24 to the nearest ten.

If the units are 4 or less, round down.

If the units are 5 or more, round up.

From the table above, 24 is between 20 and 30 but 24 is nearer to 20 than to 30. Therefore 24 to the nearest ten is 20.

Example 2:

Round 16 to the nearest ten.

Solution

16 is between 10 and 20 but 16 is closer to 20 than it is to 10. Therefore 16 to the nearest ten is 20.

Example 3:

Round 27 to the nearest ten.

Solution

27 is between 20 and 30

27 is nearer to 30 than to 20.

27 to the nearest ten is 30.

Example 4

Round 55 to the nearest ten.

Solution

55 is between 50 and 60.

55 is nearer to 60 than to 50.

55 to the nearest ten is 60.